Laser Cutting DIY

I should have said “laser diode cutting” but did not want to spoil a great looking title I had this CNC setup for about a year now and and have been tinkering with different setups for the laser diode but only recently have made any progress.

SAFETY FIRST!
Please make a note that if you are going to do this yourself, you owe it to yourself to buy a pair of nice ($35 or so) color filter safety glasses designed for the particular wavelength of the laser you are going to use. Mine is 650nm – red. I specifically wanted a laser in the visible part of the spectrum – if it’s going to burn my eye I want to at least know about it and give my reflexes a fighting chance to blink and shield my eye(s) from more damage. An infrared might have been more efficient and less picky about colors (with red laser forget about cutting any light colored material) but it requires more safety discipline.

The CNC machine it’s based on is Sable-2015 which I bought in the Summer of 2009 from eBay seller Luke-Chen in China. I have also bought the controller and the 24V DC power supply from Luke-Chen and had it running within hours after the package came in the mail.
The original idea was to use it for PCB milling but I got hooked onto laser cutting and decided to use the machine as my testbed. Below is a wider shot that shows more of the CNC router and the laser diode housing. The housing is not a more widely used AixiZ. I tried it on an earlier setup and did not like it. The one I use is black anodized aluminum and is slightly larger than AixiZ, has enough volume inside to house the driver PCB and dissipate the heat that both the driver circuit and the diode produce. I bought the TTL-controlled driver and this “upgraded” housing from an eBay seller o-like1983. It was shipped from China but came rather quickly and was very much worth the wait.

You’ve probably noticed how painfully slow this process is. In the videos above it’s actually running at 50 mm/min. This is the speed that I’ve found that works best with blue colored foam. When I’m using black foam (which I use for majority of the projects) it cuts very well and clean at 100 mm/min. So, unless you really do need color, stick with black foam.

There is one more good reason to cut quicker – the laser diode as well as the driver get really hot which means that they are probably not going to last as long as the manufacturer intended. When inside the housing, you can feel the heat but it’s OK to touch. If you were touching the driver (not so much the laser) while ON, you’d burn yourself for sure. I actually have an extra driver as well as extra laser diode for just in case. This machine has cut probably 4 hour in total so far. This very cut you see on the video is the longest I’ve ever done – 47-some minutes.

Here is how the finished product looks like:

Rocket CNC cut from 2mm craft foam

I’ll be posting more on the subject and will be making the GCode and SVG files for both the rocket and the launchpad stand available for your free downloading pleasure later.

29 Responses to “Laser Cutting DIY”

hello, Jeff Keyzer,i am a vistor from china.
i saw the laser cutter you have built,it’s very nice.and i want to ask that have you even try to use it to make PCB?I mean you can use it to remove the copper you don’t need.
best wishes ,forgive my poor english.

Hi, thank you for stopping by!
I haven’t tried PCBs yet although this machine was designed to do just that. You may want to check this discussion at cnczone: http://www.cnczone.com/forums/showthread.php?t=62815 Make sure to follow posts by mk77 – he actually shows a few samples of PCBs milled on this machine and he also devised some very nice additions to the machine – the vacuum table sounds like an indispensable device for milling PCBs , so check it out.

awesome video. what program are you using to control the sable. I will be purchasing this this month and wanted to know the best software to buy for it because the seller said it doesnt come with software

I’m using EMC2 from LinuxCNC.org It’s a free download, you should give them a try. It needs Linux to work, obviously, but you can install Linux alongside Windows if you have to. Since I have a PC dedicated to running the router, I just grabbed their Ubuntu Live CD with EMC2 distribution built in and installed it as the primary (and only) OS on this computer. Then upgraded Ubuntu as they went from version 8.04 (which is what EMC2 Live CD is built on) to 9.10 and then 10.04

I have seen people recommend other CAM software, more specifically designed for 2D cutting like what I’m doing here but I’ve yet to try anything other than EMC2. EMC2 does much more than I need for this purpose but it is free (and most other CAM software is not) and I sort of got a hang of it now, so it’s easier for me to just keep using it.

Hi Ali, thanks for stopping by!
The laser diode itself is rated at 160mW ( milliwatt, as in power) but I would have to be honest I don’t really know what the actual voltage across the diode as well as the current is: the whole housing is so tiny that it’s hard to get the multimeter’s probes to it. I would guess it must be running at close to the maximum or even higher because it does get really hot.

I am using this driver : http://bit.ly/9ZkMnZ . That’s an eBay auction of the same seller I bought mine from. This particular driver is rated 200mW. I think it’s close to the output of the laser diode I’m using.

The housing is here: http://bit.ly/9TcM2b I like this housing because it’s a bit larger that the more common AixiZ and provides better cooling. it is also much easier to put together than AixiZ because everything just screws together and you don’t have to press your diode in it as in AixiZ. I like that because I have a feeling that my diode won’t really last long because I’m using it at its limits and I’ll need to be able to replace it easily.

Yes, you do have to turn the laser diode off during the cutting – at least when the router moves between the shapes to be cut. otherwise, if the diode is still on (and I had that on earlier versions of this setup), it burns unsightly traces on the foam. That’s why you really need a TTL-controlled diode driver so you can turn it on and off from within your Gcode program.

[...] the resulting G-Code files for the Retro Rocket and its pedestal that were described in the first Laser Cutting DIY post. The files are compressed into a zip archive that can be downloaded from the CNC Files page. [...]

[...] Basically, its author describes building a laser diode cutter not unlike the one I’m using here but based on parts of discarded DVD-RW drives. In fact, the diode he’s using is also salvaged [...]

[...] PCB version 1.2, populated. I’ve been using an off-the-shelf laser diode driver for my CNC laser cutting projects and came to realize that I need a different driver. Maybe not so small as to fit inside the laser [...]

I’m using simple 2mm craft foam, the stuff you usually find in the kids section of Michael’s Arts & Crafts or another one of your favorite craft supply stores. They don’t normally say what it’s made of but some Internet research I’ve done before suggests that most suppliers make it out of EVA (Ethylene Vinyl Acetate). Cross-linked Polyethylene foam is another possible choice but it’s mostly used in packaging material. On this picture you can see the foam’s label in the corner – that’s what I use most of the time.

I think that your problem may not be the material of the foam as much as a badly focused laser. See if you can get the spot down to 0.1mm or so, or, in other words, as small as you can possibly still see (warning: focusing has to be done in safety glasses only!) . This way the energy of the beam will be more concentrated and it will what they call “ablate” i.e. evaporate the material instead of melting it and subsequently burning it.

Also try to use a fan to blow the fumes off so they don’t catch on fire themselves and don’t obstruct the beam.

Hi from France,
2 questions for you :
Have you tried to cut white EPP (Expansed polypropylen) foam ? THis material is used a lot for indoor RC planes ?
Have you tried to cut a large part of polystyren (6 or 8cm) ?
Thanks a lot in advance for your answer.
regards

Actually, the best material I ever tried to cut with these low power lasers is black-colored extruded polystyrene foam (XPS) where you can possibly go up to 5-6mm thickness. I am not too sure about EPP (and unfortunately have no sample handy to try) but from what I can read about it on the Net, it’s a material that’s even less dense than polystyrene and has even lower melting point. Although in laser cutting there’s no melting going on – there’s ablation i.e. instant vaporization of material – I think it’s reasonable to believe that EPP would ablate even easier than XPS.

The color is going to be very important – all your models will have to be black or another very dark color with no hint of red ( or the color of your laser if it’s not red).

Additionally, the thickness you’re talking about – 60 mm to 80 mm – is not achievable regardless of the laser’s power due to inherent kerf (difference in cutting width at different depth) because cutting lasers have very short focal distances. In other words, it does not cut like a Star Wars light-saber, it cuts like a magnifying glass burns wood on a sunny day when you train it to Sun and catch that focal point right on the wood surface.

So, yes, I think you would have no problem cutting your wings, stringers and any other flat elements of the airplane.

I’m about to start a CNC development also based in diode lasers from DVD-RAM, but I’m not sure about how to drive the laser. Would it work if I use a driver of the same kind that run the other two axis? I’m planning to do is modulate the current the laser is receiving via using the output from a parallel port. Is this right?

Hi Sebastian, you need a constant current driver to energise that laser diode. I have a laser diode driver schematics here. There are other laser diode driver implementations here but I thought being able to control it with a TTL-level signal was especially important. Coincidentally, I have just received the PCBs made up by Olimex for that particular driver. Will populate one or two in the next couple of days and post about it.

You can modulate it, too, but I haven’t gone this far myself yet. Basically, the limitation has been that the laser diode has a pretty weak output to begin with, and by modulating it you’d make it even weaker. But I think you can modulate it to some degree using my circuit. Even though I was only concerned about controlling ON/OFF with a TTL signal, I remember something from the datasheet saying about 10KHz rate – it may be the upper limit of your modulation frequency.

I don’t know if you’ve been to this page yet but I’ve started to document my own DVD-CNC build here. I’m currently quite busy at work and haven’t done much lately, but that’s where I plan to post any new info about DVD-CNC.

Would you have the svg file for the model ?
(or any format I could open in illustrator or 3d software). It will sound silly but I think it looks really cool and would love to use it to make a centerpiece for a rocket birthday party for my son 1yo.

I was wondering if you measured the size of the spot when it is focused. if yes, what was its size?
What housing and lenses did you used? (I am sorry to ask this as it was already asked, but the link you gave as an answer is not working anymore)
Have you tried to cut any paper? if yes what weight? 90g/m2 or more?

thanks and congratulation for this cutting machine (and the up coming one based on DVD players.

As far as the size of the hot spot (which is not the same as the size of the bright light spot) – I estimate it to be about 0.1mm . I’ve never done accurate measurements of it but just by looking at existing cuts, I’d say 0.1mm is pretty close to what’s achievable with these lens/housings.

I haven’t cut any paper with it although I experimented with some black colored craft paper. Paper is just way too dense for any practical cut done by 200mW (give or take) DVD laser diode. Since the laser is not powerful enough to ablate the material (i.e. just evaporate it), it makes it start smouldering and the edges get black and uneven. Also, if and when it cuts paper – only very thin, less than 50g/m2, and only very dark, preferably just black – it’s so very slow that just makes no sense. I only use the DVD laser diodes on 2 and 3 mm craft foam that cuts very clean and at a reasonable 100mm/min rate.

I have a 1W IR laser diode I’ve yet to find time to play with, I think I would like to try cutting paper with it again. I’m almost certain heavier card stock still won’t be possible and I’m certain white paper would not budge at all, it’ll just reflect pretty much all of the light energy needed for heating it. So, dark thin craft paper is the best candidate. Actually, I would just be happy if I can cut thicker (9mm) foam with it fast enough and hopefully add some colors to the list of what’s possible. Right now even foam does not cut at all (not even a sign of melting) if it’s anything red or anything lighter than navy blue.

I was asking for cutting paper because there are videos on youtube showing laser diode cutting paper such as here http://www.youtube.com/watch?v=tYM3VkXxSbY&feature=share&list=UU5CpdK1Htl_7xw0Oojc09fg
It is a 2W 445nm laser diode, it is true that it is quite different from your system.
By the way, I hope you are wrong and it is possible to cut properly thick paper with a laser diode because I am in a project of CNC laser cutting machine. In any case I learn plenty of stuffs so even if it is not working it will not be a total waste of time.

Well, take a look at the edges of the cuts on that video. They are charred and you would not want that for any practical application I can think of. Well, OK, I don’t know what would you use the paper cutouts for but I would probably start making aeroplane models out of them and I wouldn’t want burnt edges, I would want clean cuts. I believe with laser cutting and bright colored (or white) paper you really need a serious 30W+ IR CO2 laser to make it look like it was cut and not torched.

To be fair, he’s holding the laser diode in his hand and that’s just terrible for focusing, I guess we can safely assume that the width of the charred edge will be less on a properly mounted diode with proper optics. Ideally, it may be so small as to be passable, have to try it. You are right, there’s a great difference between a 200mW and a 2W laser and there’s also difference in their effects because of the different beam color.

Anyhow, if you want to try cutting with a 2W laser diode (of any color), I would be very interested to hear about the outcome, please come back here and post about it.

Hi,
I have a similar CNC router-scriber. I’ve never gotten it up and running. However, I have a need to make laser cut wood parts for my railroad hobby.
Any suggestions about the type of laser to use and the accuracy for cutting 1/32″ and maybe 1/16″ basswood?
Thanks.
Doug vV

The accuracy of the router is far better than the size of the cutting hot spot I was able to achieve using the optics and housing that you see in this post. It’s hard to measure the cut width exactly because I pretty much cut only foam and it does not hold shape well enough to give a good reading. But based on my attempts to cut small slots next to each other, the combination of the cutter accuracy / laser hot spot size can get you about 0.1-0.2mm accuracy (.004″-.008″)

As far as cutting wood, the laser diode will have to be changed to a more substantial one. I’ve yet to try my 1W IR laser diode (for I can’t devise a safe way to focus it with the accuracy I just described for the red laser diode). But I suspect that even 1W would have a really hard time cleanly cutting basswood. Balsa perhaps but not basswood. However, laser diodes are available all the way up to 5W (unless you want to play with very expensive arrays that combine output of several). Perhaps there’s a laser diode out there that’s powerful enough to cut 1/32″ basswood. I did not have a chance to play with one yet.

Anyhow, I think it is more realistic to expect good cuts of dense wood from even more powerful 15W+ CO2 laser cutters.

I used Sable-2015 with a 200mW laser diode (focused into approx. 0.1mm spot) riding on it, on the router attachment, and cut 3-6mm craft foam. But I would have to say cutting 3mm paper, especially not black, is absolutely out of question with a low-power laser diode like that. I never got around to try a 1W IR laser diode I got, perhaps some paper can be cut with that. But just in general, paper is very dense (as far as these small lasers are concerned of course) and is very effective at conducting heat away from the cut. Needless to say, white paper will be especially challenging since it does not absorb much of the energy in the first place.

For reliable and fast enough results (and to avoid possible fire) you’re probably going to need a serious 30W+ setup. I have seen Chinese laser cutters in that range for less than $1K on eBay – not sure if they are worth the try but the price was very appealing to me. Maybe one of those days I’ll try one … For now though, I am only cutting craft foam and black Styrofoam.

When I originally commented I clicked the Notify me when new comments are added checkbox and now every time a comment is added I get 4 emails using the same comment. Is there any way you may take away me from that service? Thanks! gadgkegcecdk

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